Tailoring Electronic Structure and Acid-Base Properties of MgO by Ce Doping Promotes Biomass-Derived Formic Acid Production at Room Temperature

Abstract

Biomass-based monosaccharide oxidation for formic acid production is significant due to its potential to provide a sustainable bio-based alternative to the traditional fossil fuel-derived methods of formic acid synthesis. In this study, we developed a Ce-MgO catalyst by incorporating Ce to enhance the oxidation of glucose to formic acid. Compared to unmodified MgO, the Ce-MgO catalyst exhibits an increased number of basic sites and higher charge densities at the Mg and O sites. These modifications facilitate the selective dissociation of hydrogen peroxide to form •OOH species and enhance the adsorption of •OOH at the MgO sites. The electron-rich nature of these Mg (OH)(OOH) active sites reduces the energy barrier for the C-C cleavage and oxidation reaction through more efficient electron transfer. Consequently, the reaction can be conducted at room temperature and achieve a 97.34% conversion of glucose and 93.65% yield of formic acid, which represents the highest performance among all glucose oxidation catalysts for formic acid production. Furthermore, the Ce-MgO catalyst demonstrated its efficacy in catalyzing the oxidation of a mixed sugar solution derived from corncob, achieving a formic acid yield of 49.13% at 30 °C. Moreover, the formic acid produced via this process allows for in situ hydrogen production at room temperature, highlighting an effective and sustainable approach for generating green hydrogen from biomass.